JP2668016B2 - Polishing pad and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing pad used for polishing various works such as metal, plastic, glass, and ceramic, and a method for manufacturing the same.

[Prior Art] Conventionally, a suede cloth has been generally used as a polishing pad when polishing various works as described above, particularly when performing final polishing. This is because the suede cloth has a surface condition that is soft and durable and easily holds the abrasive.

However, in recent years, the mirror surface condition required for products has become even more precise, and various polishing pads having higher performance than conventional suede cloth have been developed to meet the demand.

As an example, for example, in FIGS. 12 (A) and (B),
A polishing pad formed by coating a urethane resin 2 having a large number of holes 3 on a base sheet 1 is shown. However, such a polishing pad has a limitation in polishing accuracy due to a structural problem based on the manufacturing method. However, it is not suitable for precision polishing which requires high precision.

That is, this polishing pad is obtained by coating the foamable urethane resin 2 on the base sheet 1, immersing it in water to foam the urethane resin 2, drying it, and then grinding the surface of the urethane resin 2. However, since the formation of the holes 3 is left to the foaming of the urethane resin 2, it is impossible to make the size, shape, depth, etc. of the holes 3 uniform or to make the distribution uniform. Nearby, their variability was very large.

For this reason, it is difficult to uniformly hold the abrasive grains over the entire polishing pad, and it is not possible to eliminate variations in the polishing rate, the life, and the like. Is difficult and
There were many obstacles in automating the polishing process. Moreover,
As can be seen from a comparison between FIGS. 12 (A) and 12 (B) and FIGS. 13 (A) and 13 (B), the surface condition of the pad changes irregularly with its wear, and the polishing conditions tend to change. There was also inconvenience.

[Problems to be Solved by the Invention] An object of the present invention is to provide a polishing pad in which the size, shape and depth of each hole are constant and the distribution is uniform.

[Means for Solving the Problems] In order to solve the above problems, the polishing pad of the present invention is configured by adhering and integrating a porous synthetic resin having a large number of holes on a base sheet. Cage,
The voids are formed by dissolving and removing the short fibers planted in the synthetic resin.

In addition, the method for manufacturing a polishing pad of the present invention is a method in which a large number of short fibers having a predetermined thickness and length are planted on a base sheet, and a synthetic resin is applied to the short fiber planting surface of the base sheet. By melting and removing the short fibers, a large number of holes are formed in the synthetic resin.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

In manufacturing the polishing pad according to the present invention, first, as shown in FIG. 1, a base sheet 10 made of a nonwoven fabric made of polyester fiber or the like is prepared,
On one surface of the base sheet 10, a large number of short fibers 11 having a predetermined shape and dimensions are planted in a standing state by, for example, an electrostatic flocking method.

The short fibers 11 need to have a property of being dissolved by a solvent such as an acid, an alkali, water, or an organic solvent. For example, a metal such as aluminum, a plastic such as polyvinyl alcohol (PVA), or a ceramic or the like can be used. It is formed.

Further, the shape and dimensions of the short fibers 11 are the material of the work,
It can be arbitrarily set according to the type of abrasive used, the purpose of polishing, and the like. For example, a cylinder, a prism, a cone, a pyramid, a spindle, as shown in FIGS. It has a polygonal spindle shape, a drop shape, etc., and the maximum thickness is several to several hundred μ.
m, a short fiber having a length of several μm to several mm can be used. In particular, when forming a pad used for polishing a semiconductor wafer, the thickness is 30 to 50 μm and the length is 50 μm.
It is preferable to use short fibers of about 0 to 600 μm.

In the illustrated example, cylindrical short fibers 11 are used.

When the short fibers 11 are planted by the electrostatic flocking method, a device as shown in FIG. 6 is preferably used. This includes an upper electrode 22 equipped with a vacuum chuck means communicating with a vacuum pump 21 in an acrylic container 20, and a telescopic arm 24.
And a lower electrode 23 that can be moved up and down by means of which the base sheet 10 coated with an adhesive 25 is adsorbed and held by the upper electrode 22, and the short fibers 11 to be planted are placed on the lower electrode 23. Then, when a DC negative high voltage is applied to the lower electrode 23 while the upper electrode 22 is grounded, the charged short fibers 11 stand on the base sheet 10 at substantially constant intervals as shown in FIG. It is adsorbed in a state and adheres integrally with the adhesive 25.

Next, as shown in FIG. 3, the urethane resin has a thickness (for example, 500 μm) on the fiber planting surface of the base sheet 10 on which the short fibers 11 are planted, such that the ends of the fibers 11 are exposed. After coating and drying, the short fibers 11 are dissolved and removed with a solvent such as an acid, an alkali, water, or an organic solvent. A polishing pad having a large number of holes 13 constituted by 11 holes is obtained.

Here, when the short fibers 11 are dissolved in a solvent, acid is used in the case of aluminum short fibers, water is used in the case of polyvinyl alcohol short fibers, and the like depending on the material of the short fibers. It goes without saying that a suitable solvent is used.

Moreover, when short fibers other than the cylindrical shape are used, it goes without saying that holes having a shape suitable for the short fibers are formed.

The polishing pad thus formed has short fibers 11
The size and shape of each hole 13 formed in the trace where was removed,
Since the depth, distribution, and the like are almost constant, the polishing rate and life are constant as a whole, and very high-precision polishing can be performed without changing the surface state due to pad wear. .

When the short fibers 11 are planted on the base sheet 10 as described above, the short fibers 11 may be planted in an inclined state as shown in FIG. As described above, a polishing pad having the inclined holes 13 can be formed. Therefore, by controlling the inclination angle and the inclination direction of the short fibers, each hole is uniformly inclined in the circumferential direction, one in which the inclination direction is changed for each region, one in which the inclination is random, Various types of polishing pads can be obtained depending on the application.

As described above, regarding the method of inclining short fibers,
If the short fibers attached to the base sheet are physically pushed and inclined, or if the short fibers are magnetic,
As shown in the figure, there is a method of applying a magnetic field to the short fiber 11 by the magnet 26.

Furthermore, upon planting short fibers on the base sheet 10,
By patterning and applying the adhesive 25 by screen printing or the like, the short fibers 11 can be planted along the pattern, whereby, for example, FIG.
As shown in (D), it is possible to form a polishing pad having holes 13 in a specific patterned area 27.

[Effects of the Invention] As described above, according to the present invention, a large number of short fibers are planted in a synthetic resin, and holes are formed by dissolving and removing the short fibers. A large number of holes having a size, a shape, and a depth can be uniformly distributed and formed on the front surface of the pad, so that a polishing pad having a uniform polishing rate and a constant life can be easily obtained. .

Further, by using such a polishing pad, it is possible to perform highly accurate polishing without causing scratches.

[Brief description of the drawings]

1 to 4 are cross-sectional views of a principal part showing a method of manufacturing a polishing pad according to the present invention in the order of steps, FIG. 5 is a front view of the polishing pad of the present invention shown in FIG. 4, and FIG. 7A to 7G are perspective views showing examples of short fibers, and FIG. 8 is a main part when short fibers are planted in an inclined state. A sectional view, FIG. 9 is a partial sectional view of a polishing pad obtained thereby, FIG. 10 is a sectional view showing an example of a method of inclining short fibers, and FIGS. 11 (A) to (D) are formation of pores. FIGS. 12 (A) and 12 (B) are a partial sectional view and a front view of a conventional polishing pad, and FIGS. 13 (A) and 13 (B) are a sectional view and a front view showing a worn state thereof. is there. 10 …… Base sheet, 11 …… Short fiber, 12 …… Synthetic resin, 13 …… Void.

Claims (2)

(57) [Claims] 1. A base sheet is constituted by adhering and integrating a porous synthetic resin having a large number of pores, and the pores dissolve short fibers embedded in the synthetic resin, A polishing pad formed by removing the polishing pad. 2. A large number of short fibers having a predetermined thickness and length are planted on a base sheet, a synthetic resin is applied to a surface of the base sheet on which short fibers are planted, and then the short fibers are dissolved and removed. By doing so, a large number of holes are formed in the synthetic resin, and a method of manufacturing a polishing pad.